"EL" wrote in message
ups.com...
[EL]
Not at all, you are absolutely correct with your explanation.
The issue is whether such an explanation is anywhere realistically
satisfactory or can be regarded as sophisticated nincompoop that has no
physical relevance whatsoever.

I agree with you here. The use of the balloon is simply an aid to explain
what can often be a difficult concept to beginners.

I am quite certain that you are conveying the textbook's nincompoop
quite honestly, and you get the credits of being knowledgeable and
honest, but no one can blame you for conveying what was authentically
fabricated as the most ridiculous model that has no resemblance to any
logical scenario.

Yes. There are issues with how realistic a model it is. However, for its
role it is suitable. If you need to explain the concept of a universe
expanding without anything needing to move it can be helpful. I am not sure
what would prove to be a better analogy.

Those who authored that model deny space to exist without matter, while
severely falling into a contradiction assuming that that nonexistent
space is centre-less and expanding, thus pushing the 2D membrane
outwards.

Interesting concepts.

The model is a teaching aid and shouldn't be attributed with any scientific
credibility for anything else. The model really shouldn't be used to attempt
to predict any thing or create new theories. I don't think its fair to state
the "authors" of the analogy (if anyone ever knows who first came up with
the idea!) are attempting to deny anything. If, you must it become obvious
the model denies the existence of a third spatial dimension let alone
anything else.

Its an important part of cosmology to assume the universe is centre-less.
This doesn't imply that everything within the universe is centre-less. For
example, my car has a "centre."

We always look at compounded histories of light, and nothing is where
it seems to be now. Thus, the most outer is not expanding in the sense
of going away from us now, but rather WAS going away very long time ago
from where we came to be before we ever come to be. If what we see now
to have been going away then was coming closer later, much later that
we need a long time to realise that it is contracting, then why does
anyone persist to claim that the universe must be expanding now if we
do not even what light looks like now if it needed billions of years to
arrive to smash our numb senses?

EL

The problem with cosmological studies, is by the very nature of it you are
looking at things that happened in the distant past. Claims about the
expansion, contraction (or both) of the universe are based on the principle
that we do not occupy a significantly important point in time. It is
entirely possible that the cosmological expansion we see 1x10^9 ly away is
simply an ancient remnant, and "now" the "edge" of the universe is rushing
back towards us. However, there is no way to ever test this theory so it
must remain outside the realms of science for the time being.

One important point in favour of continuing expansion is that large scale
structures we see close to our local group are also expanding, in line with
the rate we see at the edge of the visible universe. This implies that the
expansion that occurred 13 billion years ago was still occurring a mere few
hundred years ago.

Still, as I said it is an interesting theory.